Electric prepayment supply system



Jan. 14, 1930. R, HORNBY, ET AL 1,743,777

ELECTRIC PREPAYMENT SUPPLY SYSTEM Filed Dec. 2l, 1926 Patented Jan. I4,1930 ROBERT OBNBY AND EDWARD HOWARD WRATTEN, F LONDON, ENGLAND nLncraIcrnnramnn'r SUPPLY srsrnm Application filed December 21, 1926, Serial No.159,224, and in Great Britain September 28, 1926.

rangement will serve as a collecting box or register for the-weekly orother instalments,

and if the hirer fails to keep up the payments by the insertion of thenecessary coin Vor instalment periodically, then the circuit isinterrupted automatically at the end of the period last paid for, andremains broken until restored bythe insertion of a fresh coin or coins.The actual consumption of energy is'ineasured by a separate meter of anysuitable kind, used in combination with the coinslot apparatus. Thesystem works however, independently of the current used, and stilloperates to break the circuit at the end of the pre-paid period even ifno current has actually een used.

In this way the use of the system provides an incentive to the user orhirer to keep up his payments regularly even if he should not berequiring to make use of the circuit, or the appliances hired, duringthe period covered by the instalment. Moreover the apparatus will serveboth as an instalment register and a collecting box, so that it willonly be necessary or a collector to call, say once aquar# ter to takeout the coins, instea of having to call for them each week for instance.

According to the invention, the time-limit device or interrupter is soarranged that after a pre-determined time, a fresh coin must be insertedto obtain a supply whether any current has been used or not. For thispurpose the apparatus comprises in combination, an ordinary energy meterand an automatm switch or interrupter provided with a device for openingit after a pre-determine period, say a wee for instance, although 1nsome cases (such as when applied to a gey ser) the period may be only aquarter of an hour for example. The timing device may comprise aconstant-speed motor or a clockwork arrangement, and be coupled to theswitch by mechanism which, after one run, is re-set for a further runsimply by the insertion of another coin and the closing of the switch.

In order that the invention may be clearly G0 understood and readilylcarried into eect, reference will now be had by way of example to theaccompanying diagrammatic drawings, in which:

Fig. 1 illustrates one arrangement of a s stem such as referred to,intended chiefly gol: collectingweekly instalments.

Fig. 2 illustrates in principle, the essential part of the coin-slotmechamsm which is employed. I p

The left-hand portion of Fig. 1 re resents the timing device orconstant-Spee motor. The right-hand portion shows the coin-slotmechanism which may be of any suitable known construction and containsthe automatic interrupter or switch and its controlling cam. The middleportion represents the reducing gear4 which serves to connect theswitch-control cam with the timing motor,

and is-so adjusted that the said motor kwill have to run say for a weekin order to turn back or reverse the control cam by the same amountwhich it has been put forward (or wound up) on the insertion of the coinor coins. At the bottom is indicated an ordinary 8x5 consumers'circuit,the supply to which is to be pre-paid for a certain time. p

-The timing mechanism illustratedresembles in general arrangement, adisc motor such as used in electric meters. a is the disc; v9B

b* the actuating or `driving ma ets,.`and c 4the brakemagnet,y thesemagnets eing laminated in 'the ordinary way. g

d1 d1 are the consumers mams. In these are included an ordinary meter alfor measuring the actual energy consumed, such energy being delivered bythe supply mains D. e represents .the automatic-control cam,

which is driven slowly -from the timing m0- tor aand allows the switch'fto spring openlpoo K after a pre-determined interval and interi'upt thecurrent to the apparatus to be controlled, such as a domestic motor g ora set of lamps.

In order that the speed of the dise motor a may keep practicallyconstant and that it may be independent of ordinary working fluctuationsin the supply voltage or potential, the magnets b c may have theirexciting coils b1 o? connected in shunt across the consumers mains d1.Thus if the potential drops and slightly reduces the force of theactuating magnets, this is compensated for by the brake magnet c beingcorrespondingly weakened at the same time, and hence the speed of thedisc a is not materially affected.

The magnets b b* have (in the ordinary way) a closed-circuit winding b2which, like a transformer winding, is energized from the shunt windingb1 and sets up thenecessary phase-reaction.

The coin-slot mechanism illustrated will now be briefly described forthe sake of clearness, although its construction is not part of theinvention. This mechanism isprovided with a casing F having the usualcoin slot f1, the winding handle or key f2, and a wii.1 dow f8 throughwhich the counter or dial is read. Internally (as in Fig. 2) itcomprises an epicyclic or differential toothed gear L h1 11.2v forworking the switch-control cain e. This cam e is mounted at one end ot amain spindle e1 from which extends a radial. arm e2 carrying the planetpinion h2 of the differential gear. At the other end of the main spindlee1 is the pointer e3 of the dial.

The two opposed discs or crown-wheels hh of the differential gear arecarried by sleeves h3 free to turn on the spindle e. The righthand disch1 is geared as shown by a suitable set of tooth wheels i1, with thecoin-receiver or drum c'. When a coin is inserted into the latterthrough the slot f1, and the key f2 is turned in the usual way, theswitch f closes and completes the circuit. At the same time the drumimparts a partial turn'to the disc h1, which causes the planet .pinionand arm e2, to travel forward with it, so turning thespindle e1 andputting the cam e into the position for keeping the switch closed.

During this motion of the pinion h2, theother disc h remains stationary.Said disc h is however geared through a pinion h* and the reducing gearj, etc. (see middle of Fig. 1) to the timing arrangement a. Consequentlywhen the control switch f is closed, the cui'.- rent starts the motordisc a and the latter very slowly turns the disc h in the oppositedirection to that in which the disc h1 was turned, so causing the planetpinion h2 and the arm c2 tovtravel back towards its original position.

In this movement the radial arm e turns the spindle e1 and control-cam eback to the pojnt where, after the lapse of the period of time which hasbeen paid for, the said cam e releases the tail orcatch f* of the switchf, thus allowing the latter to be opened by a spring (such as f5) sointerrupting the supply of current.A

The reducing gear j which connects the disc a and its spindle a with thecoin-slot mechanism does not call for special mention, beyond the factthat where the time period to be prepaid is a long one (such as a week)it is of a very high ratio, so that for instance after the motor disc ahas runfor a week, the cam e will only make a half turn. Between thisgear and the coin-slot mechanism are interposed removable wheels orchangegears jl j which can be changed when the rate of working is to bealtered. This may be necessary when the meter is to be adjusted to takecoins. of a diferent value, or is intended to allow a di'erent length ofsupply for the same kind of coin.

For direct-current working, the plain disc a may be replaced by onehaving a suitable winding of the known kind and a 3-part commutator, theoperating current being that of a dry-cell for instance, or one derivedat very low voltage by tapping a section of one of the mains on thepotentiometer principle. In x such a case the disc may rotate in thefield of a permanent magnet, instead of the electro ma ets b b* ofFig. 1. V

en the s stem is used for certain purposes, such as or controlling thesupply to an electric geyser (as for instance in hotels -to enable theguests to prepay for the use of a bath) the time interval required to becovered may only be relatively short, for instance a quarter of an hour.In these cases any convenient clock-work arrangement (such as that l ofan alarm clock) may be used in lace of the motor or disc a. Also theswitc f may be made correspondingly stout or heavy to take the ratherlarge currents which have to be dealt with in a geyser or heater. Theclockwork is made so that it may be re-wound by the opening of theswitch or turning of thekey f2 and be started by the closing of theswitch f.

'In some cases the apparatus may be made to collect arrears ofinstalments. To this end the timing device may be arranged to stillremain in circuit when the switch opens at the end of the pre-paidperiod. This may be provided for either by connecting the said devicedirectly in `shunt across the leads in advance of the switch, or broviding special contacts ,on the latter. ith such an arrangement theplanet pinion goes on. turning backwardbeyond the position at which theswitch normally opens. Consequently for resuming the supply two or morecoins (representing the arrears) have to be inserted before the pinionregains that position, the handle or key being of course turned afterthe insertion of each coin.

ius

' Obviously the above arrangements may be modified in various waysaccording to circumstances in carrying out the invention,

without departing from the general nature thereof.

We claim: y

1. In an electric supply system, a consumers circuit, an energy-meterfor measuring the consumption in said circuit,|a coincontrolled switchwhich both opens and closes said circuit, a constant-speed motor having'its windings constantly in shunt across the mains, and means actuated bysaid motor for causing said switch to open the consumers circuit after apredetermined time whether any current has been consumed or not, sub1stantially as described.

2. In an electrlc supply system, a consumers circuit provided with ameter, a coincontrolled switch for closingsaid circuit forapredetermined time corresponding to the value of the coin butindependent of the amount of current used, and a constant-speed tures.

electric motor to open said switch after such predetermined time, saidmotor having its actuating and braking magnets in shunt across theconsumers mains, whereby the time that the switch remains closedisindependent of iuctuationsin the supply voltage as well as o currentconsumption, -substantially as described. l' v In testimony whereof weaffix our signa- ROBERT HORNBY. EDWARD HOWARD WRATTEN.

